DHR1 (DOCKhomologyregion 1), also known asCZH1 orDocker1, is aprotein domain of approximately 200–250amino acids that is present in theDOCK family ofsignalling proteins.[1] This domain bindsphospholipids and so may assist in recruitment tocellular membranes.[2] There is evidence that this domain may also mediateprotein–protein interactions.[3]